Differential geometry

. Let [1(3): = (3(3],y{3)] he a unit speed curve in the plane. Prove that H = My\" ff]. . Let {1(5) be a unit speed curve in the regplane. Prove that if 9-5 D then 1' E I]. (Hint: Shaw there are smooth functions 3(3) and y{3} such that eds} = [57(3), at), [1']. Then use the preeus problem te shew that 3(3} = :|:[, , 1].]